biology - osmosis

Question 1

what is osmosis?

Answer 1

the movement of water from an area of higher concentration to lower concentration through a partially permeable membrane

Question 2

how to investigate osmosis using potato tissue?

Answer 2

• cut identical potato cylinders using a cork borer
• measure and record the length and mass of cylinders using ruler and balance
• add each cylinder to one of three solutions: 1M sugar solution, 0.5M sugar solution, and distilled water
• leave to rest overnight
• remove cylinders from solutions and blot with paper towels
• record the new mass and length of each cylinder
• draw graph for the change in mass (grams) along the y axis, and concentration of solution (mol/dm^3) along the x axis

Question 3

why should you use a cork borer to cut the potato cylinders?

Answer 3

results in equal sized samples so changes in mass and length can easily be compared

Question 4

why is it important to blot the cylinders with paper towels after removing from tubes of solution?

Answer 4

each cylinder may have different amount of water on its surface, so masses could vary. By blotting cylinders, it allows the mass of each one to be comparable.

Question 5

what safety precautions should be taken with this experiment?

Answer 5

handle cork borer and scalpel with care